Naloxone, sold under the brand name Narcan among others, is an opioid antagonist, a medication used to reverse or reduce the effects of opioids. For example, it is used to restore breathing after an opioid overdose. From Wikipedia
CalRx now offers naloxone two-packs for $24 to individuals, building on efforts that have reversed 355,000 overdoses and curbed synthetic opioid deaths.